It is often desirable to process webs in large rolls upon which printing of individual sheets is placed while the web remains in a continuous form. At some point subsequent to various printing and processing operations, the web may then be separated into individual sheets which may be grouped in the form of jobs to be bound or otherwise collated.
A popular form of job separation, involves the tabbing of certain sheets in a stack. Tabbing generally involves forming an extended leaf on the end of the sheet that protrudes further out than other sheets in the stack. One such tabbing process, particularly for use with zigzag folded stacks is disclosed in applicant's U.S. Pat. No. 5,065,992. However, the tabbing of cut sheets is more problematic since each sheet is separate and movable relative to the others. Thus, it is not possible to form a tab by folding one sheet on top of another to a predetermined length.
Prior art job separators have distinguished between sheet sections using a process known as jog offset. By means of this process, entire sections are offset from each other as a stack is formed. However, such stacks are awkward and more difficult to handle. In addition, it would be more aesthetically and functionally desirable to include only one section separating tab page to mark each section. Until now, however, the insertion of a single offset page into a large stack has proven difficult due to the lack of beam strength exhibited by a single sheet.
A form of jog separator is described in U.S. Pat. No. 3,871,644 to Stobb. This patent utilizes a jogger to align sheets relative to one another in order to form an even stack.
Similarly, it may be desirable to stack sheets horizontally rather than vertically. By "horizontally" it is meant that each sheet is oriented vertically such that the overall stack appears to be on its side. It is significantly easier to remove certain mid and end sections from a stack that is horizontal, since there is no need to lift any portion of the stack away to access these other sections. Furthermore, a horizontal stack may be made larger than a corresponding vertical stack since the stack is not limited by ceiling height or the reach of a person. Such a horizontal stack is also more stable since its weight is evenly distributed over a proportional area of stack support. The formation of a horizontal stack is shown, for example, in U.S. Pat. No. 4,361,318 also to Stobb. This device provides no offset to sheets.